In many datacenters, storage is typically a separate tier from application servers and access happens mostly via a storage area network (SAN). Current efforts to improve efficiency of datacenters in terms of reduced energy consumption and reduced operational expenses are focused on creating less expensive storage solutions. One way to do this is to bring storage closer to applications and computation by converging the two tiers. Converged storage advocates placing storage devices, such as solid state disks or non-volatile memory (NVM), in all servers where computation occurs and adapting the current input/output (I/O) stack to the new model. In the converged storage model, many storage accesses require crossing the network for various reasons, such as additional storage capacity, reliability, and sharing. Storage requests are therefore exchanged between all servers, and the network protocol used plays an important role.
There are many advantages to using Ethernet-based physical networks for storage. A single Ethernet network for network and storage data traffic reduces cost and complexity. In the past, there has been a significant amount of research on interconnects that scale and impose low overheads. However, such interconnects are unlikely to dominate and displace Ethernet in the datacenter. For this reason, the network protocol used on top of Ethernet plays a significant role in achieving high efficiency for remote storage access.
Current technology trends for efficient use of infrastructures dictate that storage converges with computation by placing storage devices, such as NVM-based cards and drives, in the servers themselves. With converged storage, the role of the interconnect among servers becomes more important for achieving m high I/O throughput. Given that Ethernet is emerging as the dominant technology for datacenters, reducing protocol overheads for accessing remote storage over Ethernet interconnects is becoming increasingly important.